THE BLOG
10/23/2014 01:18 pm ET Updated Dec 06, 2017

A Dynamic Jewish Calendar Mobile App

Remember the Palm Pilot? That personal digital assistant (PDA) that was all the rage back in the 1990s now seems as archaic as a sundial or abacus compared to today's impressive smartphones. The utility apps that we've come to depend on in the 21st century weren't even dreamed about back then. For rabbis, other Jewish professionals and observant Jews, there was one mobile app that we came to depend upon back in the Palm Pilot era and that was Luach by Penticon (luach is the Hebrew word for calendar).

Penticon's Luach quickly became the killer app for anyone in the Jewish professional world. In fact, I recall the dean of my rabbinical school at the time, Rabbi William Lebeau, telling the senior class that they could not be ordained from the Jewish Theological Seminary unless they had a PDA with Luach installed.

Now fifteen years later Google has created an importable Hebrew calendar and developers like RustyBrick, AvivoNet and Tebeka Software Solutions have rolled out their own versions of Jewish calendars for Apple's iOS and Android. However, Penticon's Luach is back and it is far and away the best virtual Jewish calendar for mobile devices on the market.

Penticon Technologies' Howie Hirsch, who lives in Israel, has finally completed work on a Luach version for iOS and he was happy to answer some questions I had on the new app.

When did you come up with the idea of creating a Luach app for the Palm back in the late 1990s?

HIRSCH: I always had an interest in the Jewish calendar. When I started to learn how to develop applications for the Palm, I decided to do something that could be useful. I created a small application where I could enter a date, and it would give me the Jewish Date, and vice versa. As I learned more about developing for the Palm and learned more about the inner workings of the Jewish calendar, I realized that this would be an application that would be useful for me, and for many other people.

Why do Jewish people need a mobile utility app like Luach?

HIRSCH: It's so convenient to have the information that Luach provides available to you at any time. It's particularly handy to have it together with your calendar, so that you can make sure to avoid conflicts with Jewish holidays when you are scheduling meetings or other events. It's also very helpful to know the Shabbat and holiday candle lighting time when scheduling events in your calendar. Having Luach on your electronic organizer is exactly where you need it.

In addition to observant Jews, who else uses Luach?

HIRSCH: Many Jews who are not Orthodox still observe Shabbat and Jewish holidays in their own ways. These people want to know when the Jewish holidays occur. It's still universal to celebrate yahrzeits (anniversary of a death), based on the Jewish date. Using Luach allows this to be done very easily. It's also very useful to figure out the date for a bar mitzvah and determine the Torah portion that is read for that Shabbat.

What are some highlights in the new iOS version of Luach?

HIRSCH: This is something that is very individual. Different people find different features as highlights. For me, the most convenient thing is being able to see what time candle lighting is for the upcoming Shabbat. That's right there on the home screen of Luach as soon as I open it. I also like the fact that I can view events from the regular iPhone calendar from within Luach, and I can create new events in the iPhone calendar from within Luach. This eliminates the need to switch back and forth between Luach and the Calendar when planning an event or meeting that needs to take into account the Jewish holidays or Shabbat time. Luach has the ability to be configured for the specific customs of each user. It's also really easy to find out [Shabbat or holiday] candle lighting times for any city, anywhere in the world. This is great for business trips, and vacations. Keeping track of yahrzeits is also very important. This is just the tip of the iceberg. There are many, many useful features, and which is most useful will vary greatly among users.

We might not think about the Jewish calendar on a daily basis, but it has an impact on our Jewish lives. Figuring out holidays, yahrzeits and minyan prayer times once took quite the effort, but today we have quick and accurate access to that information on our desktop computers and on the mobile phones we keep with us at all times. Having a fully functional Jewish calendar on our mobile devices helps Jewish people stay in touch with the calendar of our heritage now more than ever before.

Luach by Penticon, version 1.0 can be downloaded in the Apple App Store at or visit the Penticon website for more information. (Hirsch says an Android version is a possibility.)

Rabbi Jason Miller is an entrepreneur, educator and technology expert who is president of Access Computer Technology in Detroit. Follow him on Twitter at @RabbiJason.